In his recent video, This Old Tony demonstrated using EtherCAT servos with Mach 4. He shows how the servo drives are daisy chained and claims that the cable coming to the first drive is plugged to his computer.
Does it really work that way? I've researched the topic and have not found an option like that. I've only found Mach 4 compatible motion controllers which can control servo drives over EtherCAT. There is no information about connecting the drives directly to the computer.

Any information about the topic?

Here's the video:
https://youtu.be/otOVJv_FA8k